MT Composite 3 Blade Ding Repair?

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sdpilot

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kyle
One of my DA-40s got a ding in the prop today on the leading metal edge. I'm wondering if anyone knows what MTs repair procedure and tolerance levels are on this. I"m guessing they will require the leading metal edge to be removed and replaced but not sure who can do that and what the tolerance is in terms of grounding the plane etc.. I don't plan on flying it until hearing back from MT but was wondering if anyone out here knows? I've attached a picture of the nick in the prop.
 

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Geico266 said:
Your gonna need to return the prop to Germany for repairs. :redface:
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According to MT, all blade work can be done at their US facility.

Looking at the depth of that gouge, a metal prop would have had to go to a prop-shop as well.
 
weilke said:
According to MT, all blade work can be done at their US facility.

Looking at the depth of that gouge, a metal prop would have had to go to a prop-shop as well.
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I hope you are right, but a buddy of mine broke a tip off a three blade MT and it need to go across the pond for repairs. This was 2 years ago.
 
weilke said:
According to MT, all blade work can be done at their US facility.

Looking at the depth of that gouge, a metal prop would have had to go to a prop-shop as well.
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Would a metal prop look like that after the same impact?

My gut feel says the wood composite has more "give".
 
weilke said:
Looking at the depth of that gouge, a metal prop would have had to go to a prop-shop as well.
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Depends. I've found that MTs seem to get dinged easier. It might not have been such a significant ding on a metal prop. Also, you'd be surprised how much of a ding many props can take. I got some nasty dings on the Aztec props. My A&P was convinced it needed new blades. Talk to Hartzell, get the limits, no problem. But I probably should've had it dynamically balanced.
 
I have one of these on my DA40. I do not like the prop since MT is slow and difficult to deal with and the prop is pretty fragile. I have also had a few dings on my prop over the years. The answer to your question is it depends. Once I had a ding on the leading edge metal strip that was repaired quickly and painlessly at the service center on my field. Once I had one that was tiny but at the very tip of the prop blade on the metal edge. For this one, the entire prop went back to MT for an overhaul. The overhaul wasn't necessary but sending the prop back was, so the incremental cost was worth it to me. When I first purchased my DA40, the prop slung grease and I had to send it back then as well. For all these repairs, the work was done in the U.S. I never had it to send it back to Germany.
 
I had a pea sized dent in the leading edge of the old stlye MT 3 blade prop a few years ago. Two Diamond service centers told me it was OK and I flewwith it for over a year. A third service center told me it was unairworthy during an annual and refused to sign off so I had it overhauled a year early. Some of these dents can be filled with epoxy, others need to have the metal leading edge replaced. A prop overhaul runs about $4,600 plus shipping to the MT USA service center in Deland Florida. I don't know what it costs to just replace a single metal leading edge. http://www.mt-propellerusa.com/

There is a free Diamond owners forum and you can probably get more specific answers there. http://www.diamondaviators.net/
 
That smells to me like the shop just was uncomfortable with it (or wanted to sell a new prop), not that it was unairworthy.
 
Well hopefully I will talk to MT and find out the tolerances and what needs to be done today. Once I hear back I will post a followup as to what they say.

I checked the diamond forums but no posts dealt with this specifically.

Sent from my Nexus 7 using Tapatalk
 
Even more important- I assume your DA-40 has a Lycoming engine? If so you now face the prop strike AD.
"Any incident, whether or not the engine is operating, that requires repair to the propeller other than minor dressing of the blades; OR"
 
Ted DuPuis said:
That smells to me like the shop just was uncomfortable with it (or wanted to sell a new prop), not that it was unairworthy.
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I was thinking that myself but I was at a big disadvantage. It was a large maintenance shop and Diamond service center in the Minneapolis area and went out of business a few years later.
sdpilot said:
Well hopefully I will talk to MT and find out the tolerances and what needs to be done today. Once I hear back I will post a followup as to what they say.

I checked the diamond forums but no posts dealt with this specifically.
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Consider registering with DAN and starting a thread to address your issue if you haven't already.
Blackhawk said:
Even more important- I assume your DA-40 has a Lycoming engine? If so you now face the prop strike AD.
"Any incident, whether or not the engine is operating, that requires repair to the propeller other than minor dressing of the blades; OR"
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Not an A&P but I would think that repair of a small ding would be considered the equivalent of a minor dressing. The shop that had me send off the prop for repair nit picked everything and would have loved to force me to have the engine torn down but they didn't.
 
Gary F said:
I was thinking that myself but I was at a big disadvantage. It was a large maintenance shop and Diamond service center in the Minneapolis area and went out of business a few years later.

Consider registering with DAN and starting a thread to address your issue if you haven't already.

Not an A&P but I would think that repair of a small ding would be considered the equivalent of a minor dressing. The shop that had me send off the prop for repair nit picked everything and would have loved to force me to have the engine torn down but they didn't.
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Gary, you may well be right. It is hard to tell from a picture how big it is and I am not a mechanic.
I will say, however, that a red flag for me when I purchase an airplane or help someone purchase an airplane is a prop that has been pulled off for repair but there is no record of the AD being complied with. Obviously a prop can be pulled for issues not related to a prop strike, but if I were told that a prop was pulled and sent back to a manufacturer for "minor dressing" I would walk. Pulling a prop for repair, in my non-mechanic eyes, is not "minor dressing".
 
Blackhawk said:
Gary, you may well be right. It is hard to tell from a picture how big it is and I am not a mechanic.
I will say, however, that a red flag for me when I purchase an airplane or help someone purchase an airplane is a prop that has been pulled off for repair but there is no record of the AD being complied with. Obviously a prop can be pulled for issues not related to a prop strike, but if I were told that a prop was pulled and sent back to a manufacturer for "minor dressing" I would walk. Pulling a prop for repair, in my non-mechanic eyes, is not "minor dressing".
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Keep in mind the A&P mechanic's privileges are limited to minor repairs to props, a metal leading edge can't be blended, and thus must be replaced after the composite structure is repaired, this is not minor maintenance.
 
Blackhawk said:
Gary, you may well be right. It is hard to tell from a picture how big it is and I am not a mechanic.
I will say, however, that a red flag for me when I purchase an airplane or help someone purchase an airplane is a prop that has been pulled off for repair but there is no record of the AD being complied with. Obviously a prop can be pulled for issues not related to a prop strike, but if I were told that a prop was pulled and sent back to a manufacturer for "minor dressing" I would walk. Pulling a prop for repair, in my non-mechanic eyes, is not "minor dressing".
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Many of these smaller dings can be repaired by filling with epoxy so I would consider that to be a minor dressing. These props are fragile and I'm dot convinced that a dented leading edge implies any measurable stress on the crankshaft. I think Lycoming needs to update the teardown requirements with specific guidance for composite props.
 
Tom-D said:
Keep in mind the A&P mechanic's privileges are limited to minor repairs to props, a metal leading edge can't be blended, and thus must be replaced after the composite structure is repaired, this is not minor maintenance.
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In other words, that is not "minor dressing"? That would be my take on it if it was pulled and sent out for repair, but again, I am not a mechanic.
 
Blackhawk said:
Obviously a prop can be pulled for issues not related to a prop strike, but if I were told that a prop was pulled and sent back to a manufacturer for "minor dressing" I would walk. Pulling a prop for repair, in my non-mechanic eyes, is not "minor dressing".
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My MT prop was pulled with no prop strike. But your point is a good and why I have pictures of the nick that caused mine to be pulled. I think Gary and I were in the same position in that the shop has a big influence on this decision which can be driven by economics. My advice is that if it turns out you need a repair that costs more than $4k, spend $7k and get the aluminum prop. This will not be the first ding you get.
 
Wingsofglass said:
My MT prop was pulled with no prop strike. But your point is a good and why I have pictures of the nick that caused mine to be pulled. I think Gary and I were in the same position in that the shop has a big influence on this decision which can be driven by economics. My advice is that if it turns out you need a repair that costs more than $4k, spend $7k and get the aluminum prop. This will not be the first ding you get.
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Ive thought abot replacing my 3 blade MT with a Hartzell aluminum prop or possibly the 2 blade Hartzell Kevlar composite prop. I really like the smoothness of the wood epoxy 3 blade and the climb performance is reportedly better.
 
If it were me, I'd work with a local prop shop (as close as you can get anyway) and remove the prop BLADE and sent it to a US service center for repair. I expect all that needs to happen is removal of the leading edge, inspection of the composite and possible local repair, and installation of a new leading edge. They are designed for such repair capability.

Yingling in Wichita is an MT distributor and service center, or at least they were recently when I used them for some warranty work on mine.

If you're tempted to switch, you might redo your W&B first and add 12-30 lbs on the nose if you go an aluminum prop! See what that does to your CG and especially payload.
 
Wingsofglass said:
My MT prop was pulled with no prop strike. But your point is a good and why I have pictures of the nick that caused mine to be pulled. I think Gary and I were in the same position in that the shop has a big influence on this decision which can be driven by economics. My advice is that if it turns out you need a repair that costs more than $4k, spend $7k and get the aluminum prop. This will not be the first ding you get.
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Be aware that Lycoming and the AD defines a prop strike as the prop pretty much hitting something other than air, it does not need to be moving.
Again, I don't know enough to say if Gary or you had an incident that fit the AD criteria and even if I did know the specifics I am NOT a mechanic. This is not my "fight". It is just something to bring up in a discussion if an owner is having a prop pulled and sent off for "minor dressing".
 
Blackhawk said:
Be aware that Lycoming and the AD defines a prop strike as the prop pretty much hitting something other than air, it does not need to be moving.
Again, I don't know enough to say if Gary or you had an incident that fit the AD criteria and even if I did know the specifics I am NOT a mechanic. This is not my "fight". It is just something to bring up in a discussion if an owner is having a prop pulled and sent off for "minor dressing".
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If you hit a bug it might dent the MT prop.;) Those things are flimsy. The same pebble strike that would require and minor dressing on an aluminum prop may require a new metal leading edge for the MT. I don't understand why having a softer prop means an engine teardown is necessary for the same mechanism of damage.
 
Gary F said:
If you hit a bug it might dent the MT prop.;) Those things are flimsy. The same pebble strike that would require and minor dressing on an aluminum prop may require a new metal leading edge for the MT. I don't understand why having a softer prop means an engine teardown is necessary for the same mechanism of damage.
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First, it is not our call and as pointed out the FAA probably won't change this.
Second it is possible with metal props to have an incident that does not leave a mark on the prop but still requires a tear down inspection. With an MT or other composite prop the incident is just evident on the prop itself.
Also remember that even if a mechanic is wrong and tells you an airplane is airworthy when it is not, if you as an owner/operator are aware of a condition that makes the airplane un-airworthy you are responsible, not the mechanic who is wrong. (See FAA v. Nielson. Pilot flew a C-150 with inoperative carb heat. Mechanic used TOMOATOEFLAMES and told the pilot the airplane was airworthy. Airplane was not airworthy IAW CAR 3.)
Again, I am not saying you must have a tear down inspection and it is not my place to make that call.
 
Geico266 said:
I hope you are right, but a buddy of mine broke a tip off a three blade MT and it need to go across the pond for repairs. This was 2 years ago.
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My prop spit the leading edge while IMC ,rebuild of the prop was done in Deland Fla.
 
All this talk about composite prop issues sure makes me glad I don't own one. I know the 162 up the ramp has had problems too.
 
bnt83 said:
All this talk about composite prop issues sure makes me glad I don't own one. I know the 162 up the ramp has had problems too.
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I had a 3 bladed MT prop on my airplane and loved it.
 
I'd wager Lycoming was not thinking of MT props when they wrote the CYA AD on their engines.

Think about this, IF you pull that prop for repair for that ding, the AD applies. If you pull it for any other reason to get it repaired by MT, the AD does not apply.

are you sure it isn't leaking oil? :)
 
Funny, those giant gouges I had on the Aztec props and flew with for about 700 hours never resulted in a teardown inspection.

Met the Hartzell limits. And since the plane will never fly again, it doesn't much mattef anymore.
 
Hartzell is the devil's offspring. They force more SB's into AD's than perhaps any other aerospace company. They will stop at nothing to make you buy either new props or new hubs. It's their business model. When there's a diminishing base, and they know the numbers are small enough not to make too much of a stink, they will stick it to you as sure as I'm writing this. The number of older airframes/engines they've stopped supporting to force you to buy new blades are endless. What's worse, they force their certified repair stations to treat SB's = AD's and will not allow them to comply with the SB alone, or order those parts and still remain certified, which forces the prop shops hand. And there aren't that many prop shops that are not Hartzell certified.

Ask me how I know.
 
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MT-Propeller Service Letter SL-32C details repair limits and procedures. On page 7 they show allowable erosion sheath dents. Single dents up to 11 mm by 11 mm may be filled with epoxy if not delaminated or punched through.

http://www.mt-propeller.com/pdf/sls/sl32c.pdf

Steve
 
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MT said it was purely cosmetic and could be dressed up with epoxy which is what I had done. I viewed a few other composite props on the field and a few of them that had over 2K hours on the prop all had a few epoxy repairs done on them.
 
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